1. Field of the Invention
The present invention relates to the general art of footwear, and to the particular field of protective footwear.
2. Description of the Related Art
In recent years, a great many people are engaging in outdoor sports such as skiing as well as many outdoor activities, including working. Those who engage in these activities are often exposed to the elements for extended periods of time. Such exposure can lead to discomfort or, more seriously, to frost bite particularly in the extremities. It is therefore vital that people who may spend a great deal of time outdoors seek protection from the elements in order to prevent the occurrence of exposure and frost bite.
The cooling of the extremities, has long been recognized as a serious deterrent to performing activities in cold temperatures and various proposals have been advanced for dealing with this problem. In the case of feet, most footwear known to the inventor, which has been designed for use in cold weather, has utilized hard and heavy materials on the sole and sometimes on the uppers as well. For instance, hard rubber soles are most commonly used for winter boots and overboots. Since such footwear is generally constructed with rigid sole structures, carrying and storing the footwear can be difficult.
Also, other footwear known to the inventor, designed for use in cold weather, has utilized conventional insulating materials, such as goose down, stiff insulating foam or synthetic fibers, to reduce the loss of heat from the wearer's foot. While these insulating materials attempt to minimize the heat loss from the wearer's foot, all of these insulating materials have various drawbacks.
A foot cover that is easy to manufacture, is easy to use, is lightweight, is easy to carry, is easy to store, is washable, and is highly effective at keeping the wearer's feet warm would be of considerable value.
A variety of other devices and methods are known for this purpose. For example, footwear can be provided with insulation or made waterproof. Such methods have significant drawbacks. For example, waterproofing methods provide no manner of either retaining heat or providing additional heat to the wearer's feet. Rather, they only prevent the introduction of water or other liquid, which could make the wearer's feet cold. Insulation is largely ineffective as well because it merely retains body heat without providing any additional heat.
One method of providing a heat source in footwear involves placing an electric heating element in the shoe or boot liner and using a battery to supply energy to the heating element. Another attempt to solve the problem of cold feet has involved the use of electrical heating elements in socks. Foot warming devices that use electric heating elements have a number of disadvantages. First and foremost, they can be dangerous. Specifically, they can create the risk of electric shock, sparks that could cause flammable socks and/or footwear materials to catch fire which in turn could burn the wearer's feet, and electrical shortages. Such electrical devices can also be expensive and inconvenient to use.
It is also known to adapt the insoles of boots, shoes and the like to accommodate a heat dispensing material in a pocket formed in the insole. These devices also have significant disadvantages. Specifically, they contemplate permanently modifying the footwear itself to accommodate the heat dispensing material. This could permanently add weight and bulk to the footwear which is unnecessary, especially when the footwear is worn in warm environments. In addition, these devices do not allow for adequate circulation of the generated heat to the wearer's feet.
Some prior art foot warmers include a removable insole for footwear that has a reduced thickness portion in the padding layer creating a cavity for holding a heat source that produces heat from an exothermic chemical reaction. These insoles often have an upper layer that has a plurality of holes for facilitating heat transfer from the heat source to the wearer.
Although an improvement, these insoles also have significant drawbacks. First and foremost, the heat source is generally enclosed in the cavity in such a way that the amount of air that can reach the heat source is limited. Thus, because the heat source needs oxygen to drive the chemical reaction necessary to generate heat, the amount of heat produced is greatly inhibited. The heat source is also enclosed in the cavity in such a way that the heat generated by the heat source cannot adequately circulate so that the wearer's feet are not effectively heated.
Still further, while a person's feet have received much attention in the above-described situations, a user's hands also may suffer the same problems when exposed to cold temperatures. While the inventor is aware of several devices that are intended to keep a user's hands warm, including gloves, mittens, heated gloves and mittens, the inventor is not aware of any device that can be used for either or both a user's feet and/or hands. Accordingly, a user is required to carry items for his or her hands as well as additional items for his or her feet. This can be cumbersome and inconvenient.
Therefore, there is a need for a device that can be used to heat a user's feet and/or hands.